Generally, in the stapler, a driver side for driving a staple and a clincher side for bending the legs of the staple driven are opposed to each other so that sheets of paper to be stapled are inserted between the driver side and the clincher side. Previously known are an integral type stapler in which members on the driver side and members on the clincher side are pivotally supported coaxially as in an ordinary manual stapler, and a separated type stapler in which members on the driver side and members on the clincher side are separated and moved in the same direction. The former is effective in stapling the side end or corner of the sheets of paper such as stapling a plurality of documents in paperwork handling. The latter is effective in inserting the sheets of paper from one side between the members on the driver side and the members on the clincher side and passing them toward the other side, such as center-stapling the central portion of a magazine.
An important thing in the stapler is an alignment state in which the legs of the staple driven by the driver and penetrating through the sheets of paper surely hit against the clincher. If the alignment state is appropriate, the legs of the staple are exactly bent so that the sheets of paper can be stapled. Therefore, consideration is given so that the driver and the clincher align in predetermined positions in stapling.
In the integral type stapler, in which the driver and the clincher are supported on a common axis, they can be relatively easily aligned in their position. On the other hand, in the separated type stapler, in which the driver and the clincher are fixed by different means, it is difficult to exactly position both units. Particularly, in recent years, the separated type stapler are required to enable not only the center-stapling but also corner-stapling and side-stapling. In order to fill this requirement, the driver unit and clincher unit must be simultaneously moved in the same direction. Even if they are fixed at the same position, their alignment is difficult. In addition, when both units are exactly moved by the same distance in the same direction by separate means, respectively, not only a component tolerance but also an attaching error such as the center-matching of the stapler by a user are accumulated so that their alignment is very difficult.
In order to avoid such inconvenience, JP-A-2003-205506 discloses a stapler provided with an automated alignment mechanism which does not fix the clincher at predetermined positions of the clincher unit but supports the clincher so that the clincher is movable relatively to the clincher unit, thereby moving the clincher according to the position of the legs of the staple having penetrated through the sheets of paper. In this stapler, at receiving positions of the legs of the staple on the upper surface of the clincher holder supporting the clincher, guide faces inclined toward the clincher are formed so that the clincher holder is supported so as to be movable inside an opening formed in a stapling table receiving the sheets of paper. If tips of the legs of the staple slightly deviate from a predetermined position to hit against the guide faces of the clincher holder, the clincher holder moves together with the guide faces so that the tips of the legs of the staple are received by the clincher.
In accordance with the above configuration, even if the legs of the staple which have been driven in stapling by the driver and penetrated through the sheets of paper are deviated from the predetermined position, the clincher move to the position corresponding to that of the legs. Therefore, the legs of the staple are exactly bent, thereby giving appropriate stapling.
However, some staplers are required to staple the position apart by about 3 mm from by the side end of the sheets of paper. In this case, as shown in FIG. 9A, an opening 31 of a stapling table formed around clincher holders 30 is formed with a size larger than the clincher holder 30 so that the clincher holder 30 is movable inside the opening 31. Therefore, when the legs 11 of the staple penetrating through the sheets of paper “a”, the side end of the sheets of paper “a” may drop inside the opening 31 owing to the pressure from the legs 11. At this time, the pressure of the sheets of paper “a” is applied to the clincher holder 30. Owing to this, as shown in FIG. 9B, even when the legs 11 of the staple hit against the guide face of the clincher holder 30, the dropped zone “a1” of the sheets of paper “a” holds down the clincher holder 30 by the above pressure so that the clincher holder 30 cannot move. Further, when the sheets of paper have dropped inside the opening 31 by clamping, a sheaf of the sheets of paper “a” becomes deformed so that the legs 11 of the staple may be driven in a direction different from the direction perpendicular to the surface of the sheets of paper. This may give rise to buckling or rolling of the legs 11 of the staple, thus leading to poor stapling.